Prior art aircraft fuselage insulation primarily comprises fiberglass bats packaged in thin reinforced film bags produced by cutting, sewing and heat sealing the insulation within the bags. This process generally involves a CNC automated cutting system that cuts the fiberglass and films, and the product is then moved to an area where the multi-layered layup of film/fiberglass/film is heat sealed or sewn by individual operators. Since this involves significant labor, the majority of these insulation blankets are produced in low labor cost countries.
A significant cost in insulating an aircraft is the labor involved in installing the current fiberglass bagged insulation system. The fiberglass insulation bags do not have structural integrity and require a significant amount of mechanical fastening to hold them in position between the frames and over the stringers of an aircraft fuselage. In addition, a significant cost of the insulation parts is due to the high labor content in sewing and/or heat-sealing the bags.
In some instances, particularly in smaller aircraft or private aircraft, foam elements are used either alone or in combination with fiberglass; however they are covered in a similar manner, with covering films that are hand-sewn or hand-laminated.
In all cases the insulation and covering films both individually and as a composite must pass rigorous flame, smoke and toxicity (“FST”) standards developed by the FAA and adopted by all aircraft manufacturers.
Most thermoplastic films used in packaging are amorphous but do not have the FST properties required by the aircraft industry. In addition, these thermoplastic films are typically processed at relatively low temperatures, typically well under 300 degrees Fahrenheit. Amorphous films that have FST properties typically have higher melt temperatures greater than 400, generally between 400 and 425, Fahrenheit.